1. Field of the Invention
This invention relates to a roof construction and a roof board therefor, and more particularly to a roof board adapted to be roofed in the direction of from an eaves side to a ridge side and a roof structure constructed by such roof boards.
2. Description of the Prior Art
Conventionally, various kinds of roof boards each formed at both ends thereof with an eaves side connection and a ridge side connection through which a plurality of the roof boards are connected to one another in order from an eaves side to a ridge side to construct a roof structure have been proposed. The eaves side and ridge side connections are also intended to prevent rainwater from entering therethrough into a roof structure.
Now, the conventional roof board will be described hereinafter with reference to FIGS. 1 to 6.
FIG. 1 illustrates one example of the conventional roof board and FIG. 2 shows an engagement between adjacent two roof boards in a conventional roof structure constructed by the roof boards. A roof board generally designated by reference numeral 30 in FIG. 1 may be formed of a lengthwise steel sheet of a fixed width to which baking finish for rust prevention was applied. More particularly, the steel sheet is first subjected to a shaping process using a suitable forming machine to form the roof board 30 which has a flat surface section 32, an eaves side or lower side connection 34 contiguous to one end of the flat surface section 32 and a ridge side or upper side connection 36 contiguous to the other end of the flat surface section 32. The so-formed roof board 30 is then cut at both sides thereof to have a predetermined width. Thereafter, the roof board 30 may be formed at both sides thereof with side connections (not shown) which serve to laterally connect a plurality of such roof boards to each other in order. The side connections may be formed in a manner such that one is turned up and the other is turned down so as to be engaged with a turned-up one end of a laterally adjacent roof board.
The eaves side connection 34 of the roof board 30 is formed into a substantially C shape so as to have a top section 38 obliquely downwardly extending from the one end of the flat surface section 32, a front face section 40 downwardly extending from the obliquely downwardly extending portion 38, an inwardly extending section 42 inwardly connected to a lower end of the front face section 40 and upwardly curved at a middle portion 44 thereof, and a turned-up end section 46 formed at a distal end of the inwardly extending portion 42.
The ridge side connection 36 is formed to have a a mount-shaped section 50 formed at the other end of the flat surface section 32 so as to obliquely upwardly and inwardly extend therefrom. The mount-shaped section 50, as shown in FIG. 1, is often connected to the flat surface section 32 through a section 48 slightly obliquely upwardly and outwardly extending from the other end of the section 32. The mount-shaped section 50 is provided with a first crest 52 and a second crest 54 in turn to define a trough 56 therebetween and an obliquely downwardly directed end 58.
A plurality of the roof boards 30 constructed as described above are upwardly arranged in turn. More particularly, the eaves side or lower side roof board of each adjacent two of the roof boards 30 is first mounted on common rafters 60 through an excelsior board 62 arranged therein so as to act as a backing material using a suitable means such as fixtures, and then the ridge side or upper side one of the adjacent two roof boards 30 is mounted on the common rafters in substantially the same manner and connected to the eaves side roof board 30 by engaging the ridge side connection 36 of the eaves side roof board 30 with the eaves side connection 34 of the ridge side roof board 30 in a manner to receive the inwardly extending section 42 of the ridge side roof board in the ridge side connection 36 of the eaves side roof board and abut the obliquely downwardly directed end 58 of the eaves side roof board against an inner surface of the front face section 40 of the ridge side roof board, as shown in FIG. 2. Such mounting and connection of the roof boards are repeated, so that a roof structure may be completed.
The connection of the roof boards 30 as described above causes a first evacuated space 64 to be formed between an upwardly curved middle portion 44 of the inwardly extending section 42 and the slightly obliquely upwardly extending section 48, a second evacuated space 66 to be formed in the ridge side connection 36 adjacent to a connection between the mount-shaped section 50 and the slightly obliquely upwardly extending section 48 and a third evacuated space 68 to be defined due to cooperation among a second crest 54, the front face section 40 and the inwardly extending section 42.
Another example of the conventional roof board is shown in FIG. 3. Each of eaves side and ridge side roof boards 30 shown in FIG. 3 likewise is formed to have a flat surface section 32, an eaves side connection 34 contiguous to one end of the flat surface section 32 and a ridge side connection 36 contiguous to the other end of the section 34. The eaves side connection 34 is formed in substantially the same manner as that shown in FIG. 1. However, the ridge side connection 36 is formed in a different manner. The ridge side connection 36 is formed to have a section 48 slightly obliquely upwardly extending from the flat surface section 32, a first turned-up 50' formed at a distal end of the section 48 and adapted to receive an inwardly extending section 42 of the ridge side roof board 30 in cooperation with the section 48, a second turned-up section 70 connected to the first turned-up section 50', an upwardly projected section 72 connected to the second turned-up section 70, and a flat section connected to the projected section 72 and substantially flash with the slightly obliquely upwardly extending section 48. In the roof board 30 of FIG. 3 constructed as described above, the inwardly extending section 42 of the ridge side roof board is received in a gap defined between the slightly obliquely upwardly extending section 48 and first turned-up section 50' of the eaves side roof board, and a connection between the first and second turned-up sections 50' and 70 is abutted against an inner surface of the front face section 40, so that a first evacuated space 64' and a second evacuated space 66' may be formed between the first turned-up section 50' and the inwardly extending section 42 and in a region within the eaves side connection 34 above the second turned-up section 70, respectively.
A further example of the conventional roof board is shown in FIG. 4. A roof board 30 shown in FIG. 4 is formed to have a flat surface section 32, an eaves side connection 34 and a ridge side connection 36 like those shown in FIGS. 1 and 3. The eaves side connection 32 includes an obliquely downwardly extending section 38 connected to one end of the flat surface section 32, a front face section section 40 connected to the section 38, an inwardly extending section 42 connected to the section 39 and curved up at a middle portion thereof, and a turned-up section 46 connected to the section 42 which are formed in order. The ridge side connection 36 includes a slightly obliquely upwardly extending section 48 connected to the other end of the flat surface section 32 and a turned-up section 50 connected to the section 48 and having a distal end 58 directed obliquely downwardly.
A plurality of the roof boards 30 of FIG. 4 constructed as described above are upwardly connected in turn, as shown in FIGS. 5 and 6. More particularly, the eaves side roof board of each adjacent two of the roof boards 30 is mounted through an excelsior board (not shown) on common rafters 60 arranged to obliquely upwardly extend from an eaves side to a ridge side using a suitable means such as fixtures, and then the ridge side one of the adjacent two roof boards 30 is mounted on the common rafters in substantially the same manner and connected to the eaves side roof board 30 by engaging the ridge side connection 36 of the eaves side roof board 30 with the eaves side connection 34 of the ridge side roof board 30 in a manner to receive the turned-up section 50 of the eaves side roof board 30 in the eaves side connection 34 of the ridge side roof board 30 and fit an overall outer surface of the turned-up end section 46 of the ridge side roof board 30 in a base portion of the turned-up end section 50 of the eaves side roof board 30. Such mounting and connection of roof boards is repeated, so that a roof construction may be completed.
As can be seen from the foregoing, the engagement between the eaves side connection and the ridge side connection in the conventional roof structure is basically carried out in such a manner that a butt region between the ridge side connection of the eaves side roof board and the eaves side connection of the ridge side roof board is formed on a plane of substantially the same level as or slightly above the flat surface section of the eaves side roof board, as indicated at reference numeral 74 in each of FIGS. 2, 3 and 6. Unfortunately, this causes wind and rain blown up along a gradient of the flat surface section 32 of the roof board to concentratedly strike the butt region 74, resulting in a large pressure being applied to the region 74. This results in the butt region 74 providing a drift of dust, snow and the like and causes wind and rain blown against the region 74 to be laterally guided along the region 74 and jump up along the front face section 40.
Accordingly, as shown in FIG. 6, a pressure A of wind and rain directly blown against the butt region, a pressure B of jumping-up wind and rain and a pressure C due to the synthesis between the pressures A and B are applied to the butt region 74. It was found that the pressure A is apt to cause rainwater to enter through the butt region 74 into an interior of the roof structure due to a capillary action. The pressure B and C cause a gap to be formed at the butt region 74 which is sufficient to substantially increase the penetration of rainwater into the roof structure. In particular, it is often observed that foreign matters such as sand, mud, dust and the like accompanied by strong wind and rain enter into the roof structure and are collected therein to cause the rust and corrosion of the structure to occur due to a galvanic action and the like. Also, rainwater which once entered into the roof structure is highly hard to be discharged therefrom, resulting in the corrosion being further promoted. This also causes the rainwater to be frozen in the roof structure in winter at a cold district to further damage it due to freeze expansion.
Further, a height of the engagement between the eaves side connection and the ridge side connection is not sufficient to permit the roof structure to exhibit satisfied snow break. Accordingly, when much snow lies on the roof structure, reaction force E of snow load D is generated in the direction of further opening the butt region 74 to cause snow water to flow through the opened butt region 74 into the structure.
Moreover, in the conventional roof structure constructed as described above, a space 75 is often formed between the flat surface section 32 and the common rafters 60, as shown in FIGS. 5 and 6, so that sudden or strong wind causes the roof structure to be loosened. This leads to the generation of noise due to the beating of rain drops against the roof boards. Such noise is amplified in the space 75.
Accordingly, it would be highly desirable to develop a roof structure which is capable of forming a butt region between an eaves side connection and a ridge side connection which effectively prevents the penetration of wind and rainwater through the butt region into an interior of the roof structure and a roof board therefor.